Series stacking of DC voltage domains (photovoltaics and batteries) and Differential Power Processing (DPP) have been popular for a long time. More recently, series stacking has been successfully implemented with servers and even been shown to be feasible with microprocessor cores. As operating supply voltages of processors continue to decrease, their power supply design becomes more complicated. Series stacking of processors/cores is an attractive idea since it reduces the output impedance requirement of the processor power supply by several orders of magnitude. DPP plays a very important part in voltage regulation of a series stack of loads. The DPP converters only supply small differences in currents between consecutive loads and one stack converter supplies the average current of the stacked processors/cores. With small differential currents and relatively high stack current, it is possible to achieve extremely good system level efficiencies. However, to obtain good system level efficiencies over a wide load range (especially in the low stack current region), the light load losses of the bidirectional DPP converters have to be minimized. This presentation is on the design and control of a non-isolated DPP converter which achieves good efficiencies over a wide bi-directional load range.